That's the anti-capitalist narrative where AWS is the root cause for a small heroic company called Redis to defend themselves against the evil capitalist thieves.
In reality, the vast majority of commits on Redis in recent history weren't coming from Redis the company (a VC funded entity looking to do an IPO) at all but from the collective users of Redis. Which include such small companies as Amazon, Google, Microsoft, etc. many of whom have a long history of having offered Redis as part of their cloud platforms. Redis was benefiting enormously from these contributions. The notion that VCs somehow own this codebase and are the victim of other public companies abusing their intellectual property is nonsensical.
They unilaterally created a fork of the up until then open source code base that all these companies have been contributing to. This is completely legal under the BSD license and they are well within their rights to do so. Just like every other user of Redis. Including the before mentioned large software companies. But unlike Redis, they continue to contribute to the open source code base and share the code. It's Redis that has turned all greedy and capitalist here, not AWS. Redis never paid AWS for their contributions. Or Google. Or Microsoft. That's how open source works.
This developer community is of course continuing to work on the various forks that they already had (for the purpose of developing and contributing back changes) and will continue to share code with each other. Why would they stop doing that? Nominally, Valkey, which has been created under the Linux Foundation seems to be emerging as the dominant shared fork used for that. AWS is merely announcing that they indeed plan to rally behind that one.
It's logical, sensible, and completely consistent with what they have been doing for many years, which is to offer a Redis/Valkey based service to their users and collaborate with other users and companies on the open source code base. I expect more announcements from the vast majority of companies using redis in the next weeks. The only thing that changed is that Redis the company cut themselves loose from that ecosystem. Most of the code and business was never theirs. They owned neither the copyright nor the moral rights to any of that.